BurnInTest - PC Reliability and Load Testing

Peripheral Ports

Serial (RS-232)

Approximately 115kb/s. Industrial PCs support other serial standards (such as, RS 422/485) that support higher bandwidth (over longer distances), but these are unlikely to be a consideration for the home user. Where a choice is available, we would recommend a USB (or Firewire interface) over a Serial port interface for the home user.



Approximately 8Mb/s. We would recommend a USB (or Firewire interface) over a Parallel port interface for the home user.


USBUSB ports

USB has been through a number of iterations, USB 1.0, USB 1.1 and most recently USB 2.0. Both USB 1.0 and 1.1 support maximum throughput of 12Mb/s, termed FullSpeed. USB2.0 supports the USB 1.x modes (ie. USB 1.0 and USB 1.1 modes) as well a new mode, High Speed, that has maximum throughput of 480Mb/s. If your PC only supports USB 1.x, we would only recommend upgrading if you plan to use an external CD, hard disk, or very large external memory card. It should be noted that when upgrading via a PCI card (the typical way to upgrade from USB 1.x to 2.0 on an existing PC), the PCI bus becomes a bandwidth bottleneck. Our bandwidth test results show bandwidth of around 130Mb/s when connected with a USB 2.0 PCI card, significantly slower than when connected via the motherboard, where our test results show bandwidth of around 260 to 330Mb/s.


It should be noted that USB bandwidth decreases as you plug more USB devices in (to the Universal Serial Bus). Our testing shows the following approximate reduction in bandwidth as USB devices are added to a USB 2.0 bus connected via the motherboard.

Number of USB devices connected Bandwidth tested (Mb/s)
1 330
2 205
3 155
4 120
5 80


Find out more information about USB bandwidth testing.


FirewireFirewire ports

Firewire has two favors, FireWire 400 (IEEE-1394a) and the newer FireWire 800 (IEEE-1394b). As the names suggest, the former supports maximum bandwidth of 400Mb/s and the latter 800Mb/s. You can check the data transfer speed of your Firewire ports by connecting a Firewire storage devices and running disk test with it in Performance Test.


Internal I/O Buses

Inside your PC are a number of buses. A bus is a bit like a highway that a number of devices can put traffic onto. There are buses for the CPU, memory and I/O (Input/Output) devices. The bandwidth of the bus used will effect the bandwidth of the devices connected. PCI 32bit is pretty much the stock standard interface for high speed add-on cards, such as Network adapters and USB expansion cards. Where a choice is available, you should choose an add-on card with an PCI interface over an ISA interface.

Bus Bandwidth (MBytes/sec)
E-ISA (Industry Standard Architect). Older interface. 32
PCI 32 bit (Peripheral Component Interconnect bus).Typical current interface. 127
PCI 64 bit 508



Additional information

Our web site, www.passmark.com, provides some additional information regarding bandwidth testing. It outlines PassMark Software solutions for testing the bandwidth of PC technology and ranges from PC benchmarking solutions that provide a range of features including advanced network testing, through to specific USB benchmarking solutions.